1. Technical Field of the Invention
The present invention relates to an ink jet type recording head to be suitably used for a printer or a plotter.
2. Related Art
A related ink jet type recording head, for example, an ink jet type recording head using a piezoelectric vibrator as a pressure generating element, comprises a nozzle plate having a plurality of nozzle openings provided in a line, a passage forming substrate in which an ink passage for communicating with the nozzle openings from a common ink chamber to a pressure chamber is formed, and a vibrating plate to be apart of a diaphragm of the pressure chamber, and each member is bonded in a lamination state to constitute a passage unit and the passage unit is bonded to a case. The passage forming substrate is fabricated by etching a silicon wafer, for example, and a nozzle plate formed of stainless is bonded to one of surfaces of the passage forming substrate and the vibrating plate is bonded to the other surface. The vibrating plate is constituted by a composite plate member having a resin film laminated on a support plate formed of stainless.
In the passage unit having such a structure, the passage forming substrate formed of silicon sets limitations to the directivity of the etching and the etching should be carried out to leave a silicon crystal (111) surface. For this reason, the pressure chamber and the common ink chamber which are formed on the passage forming substrate put restrictions on shapes. Consequently, there is a problem in that a desirable shape is obtained with difficulty.
Moreover, there is also a problem in that the passage forming substrate is cut out of the silicon wafer so that it has a size restriction and is not suitable for an increase in the size.
Furthermore, there is a difference between a coefficient of linear expansion of silicon to be used for the passage forming substrate and a coefficient of linear expansion of a stainless plate to be used for the support plate of the vibrating plate and the nozzle plate. Therefore, there is also a problem in that the passage unit is flexed with a change in a temperature.